Agitation and evacuation of refinery solids waste

ABSTRACT

A method of evacuating a refinery tank containing waste with solid constituents is disclosed. The method includes inserting an agitator on a boom through a first opening on a side of the refinery tank and agitating waste in a first area of the refinery tank to cause the waste in the first area to have a first viscosity lower than a second viscosity of waste in a second area at a periphery of the first area. The method further includes removing agitated waste from the first area while maintaining the waste of the second viscosity in the second area, thereby forming a safe room in the refinery tank. The method also includes expanding the first opening toward the floor of the safe room to enable entry of a movable excavator into the safe room of the refinery tank and removing waste of the second viscosity from the second area of the refinery tank.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims the benefit of Provisional ApplicationNo. 61/752,709, filed Jan. 15, 2013, the contents of which areincorporated herein by reference.

FIELD

Aspects of this disclosure involve a mixing apparatus for mixing asubstance including solid constituents. Methods described in thisdisclosure can be used for cleaning ground tanks containing wasteincluding solids on a tank bottom, and can further involve equipment andmethods for disposing of the waste.

BACKGROUND

Residual wastes are often generated during industrial processes. In thecontext of oil refineries, the residual wastes may include byproducts ofthe refinement process. These wastes may be solids including, but notlimited to, dirt, sand, grit, paraffin, wax, and/or emulsified oil.Solids accumulating inside of a ground tank settle on a tank bottomwhich, over time, may undermine the productivity of the tank. Forexample, a tank 120 feet in diameter with a height of 40 feet, mayaccumulate tens of feet of build up at the tank bottom, reducing itscapacity and rendering it inefficient or unsuitable for use.

In the context of gasoline refineries, a catalyst is often used to starta reaction to initiate the processing of gasoline. Such catalysts mayinclude an aluminum catalyst known as CC catalyst, or otherprecious-metal catalysts such as an FCC catalyst or palladium catalyst.When the catalyst is added, it can be in the form of a solid (e.g., adry powder), which can later be extracted using one or more filtersfollowing the completion of the gasoline refinery process.

In some instances, a breach may occur in one of the pieces of equipmentthat allows catalyst to flow from a cat cracker during the processing.This flow is sometimes referred to as slop oil. When slop oil escapesand refineries try to process it, the slop oil may combine with thecatalyst to form a thick layer of solids that settle onto the tankbottom. In certain scenarios, 60% to 70% of the solids at the bottom ofa ground tank, such as, for example, a refinery tank, may comprise theslop layer. Other solids that rest on the tank bottom may include dirt,sand, grit, paraffin, wax, and emulsified oil. These solids mayaccumulate with time on the tank bottom and require cleaning.

Traditionally, in order to clean the refinery tanks, refineries pumpliquids into the refinery tank, mix the liquids and solids, and extracta blend for centrifuging outside the refinery tank. The centrifugedmixture of solids and liquids are then transported from the location ofcentrifuging to an industrial burner (e.g., cement kiln) for disposal ofthe waste materials. These methods can be costly due to the costsassociated with roll-off container rental, repair, and cleaning;shipping, storage, etc. Additionally, a considerable amount of resourcesare expended tracking the hazardous materials as they are extracted fromthe refinery tanks and loaded and unloaded at the centrifuge and thekiln.

Refinery tanks may remain in service or taken out of service as thewaste is removed from the refinery tank. Where a slop layer is present,however, cleaning may be made difficult. Before the removal of anysolids, the slop layer should be removed. This can take months,requiring the tank to be taken out of service, which can add expense.Accordingly, there is a need for an efficient process to remove,process, transport and dispose of the solids from a refinery tank.

SUMMARY OF A FEW EXEMPLARY EMBODIMENTS OF THE INVENTION

A method of evacuating a refinery tank containing waste with solidconstituents is disclosed. The method may include inserting an agitatoron a boom through a first opening on a side of the refinery tank. Thefirst opening may have been cut in the refinery tank above a top surfaceof waste in the refinery tank. A bottom edge of the opening may bespaced a number of feet from a bottom of the refinery tank. The methodmay further include agitating waste in a first area of the refinery tankto cause the waste in the first area to have a first viscosity lowerthan a second viscosity of waste in a second area at a periphery of orsurrounding the first area. The method may also include removingagitated waste from the first area while maintaining the waste of thesecond viscosity in the second area, thereby forming a safe room in therefinery tank. A floor of the safe room may be substantially coincidentwith the bottom of the refinery tank. The method may also includeexpanding the first opening toward the floor of the safe room to enableentry of a movable excavator into the safe room of the refinery tank.The method may also include removing waste of the second viscosity fromthe second area of the refinery tank using the movable excavator.

In various embodiments, the apparatus may include one or more of thefollowing additional features: the apparatus may include adding diluentto the refinery tank and wherein agitating the waste in the first areaincludes mixing the diluent with the solid constituents in the firstarea; the at least one wall of the safe room may be formed with a slopeof between 30 degrees and 75 degrees; the method may further compriseadding a support to at least one wall of the safe room; the method mayfurther comprise sampling the waste in the refinery tank and determininga minimum angle of repose of at least one wall of the waste solids inthe safe room based on characteristics of the sample; the method mayfurther comprise installing a ramp proximate a threshold of the openingto enable the excavator to be propelled into the safe room; the expandedopening may have as maximum height of over six feet; a bottom of theexpanded opening may be distanced from the bottom of the refinery tankby less than three feet; wherein during removing excavator, the methodmay include removing waste in a manner maintaining a predetermined slopeof greater than 90 degrees on at least one wall of the safe room; themethod further comprising measuring a distance between a level of wasteinside the refinery tank and a reference point; the movable excavatormay be self-propelled.

Other exemplary embodiments may include removing agitated waste of thefirst viscosity through the top of the refinery tank and removing wasteof the second viscosity from the second area of the refinery tank via asecond opening on a side of the refinery tank. In various embodiments,the apparatus may include one or more of the following additionalfeatures: a bottom edge of the expanded second opening may be spaced anumber of feet from a bottom of the refinery tank, the bottom edge ofthe second opening may be distanced from the bottom of the refinery tankby less than three feet; a combined height of the first opening and thesecond opening may be over six feet; at least one of the first openingand the second opening may be cut using a pressure water jet cuttingapparatus.

Yet another exemplary embodiment may include cutting a first opening inthe refinery tank above an initial top level of waste; inserting anagitator into the refinery tank through the first opening and agitatingthe waste in a first area to cause waste in the first area to have aviscosity greater than a viscosity of waste in a second area at aperiphery of or surrounding the first area. The method may includeremoving the waste from the first area. The method may further includeexpanding the opening downward to a location above the bottom of thefirst area and agitating the waste at the bottom of the first area tocause waste beneath the bottom of the first area to have a viscositygreater than a viscosity of waste in a second area at a periphery of orsurrounding the first area. The method may also include removing thewaste from the bottom of the first area to reach an expanded bottom ofthe first area, and expanding the opening downward to a location abovethe expanded bottom of the first area.

In various embodiments, the apparatus may include one or more of thefollowing additional features: the method may further compriseiteratively agitating, removing and expanding until the first area isexpanded to a depth proximate a bottom of the refinery tank; the methodmay further comprising sloping walls of the first area during removingin order to create a safe room in the first area; the method may furtherincluding inserting a movable excavator into the safe room andevacuating the waste of the second viscosity from the second area usingthe excavator; the movable excavator may be self-propelled; the methodmay further comprise measuring a distance from a bottom of the openingto a bottom of the first area, and using the measured distance as areference for expanding the opening; the first opening may be cut in aside of the refinery tank, and wherein prior to cutting the firstopening, a portion of the tank is agitated via an initial opening in atop of the refinery tank; the method may further comprise moving wastefrom the tank to a lump reducer; the method may further comprisedelumping waste lumps in the lump reducer using at least one blade; themethod may further comprise conveying the delumped waste to a manholeopening of a mobile tank; conveying the delumped waste may includemoving the delumped waste via a conveyor; the method may furthercomprise moving the mobile tank to a burning facility; the method mayfurther comprise adding diluent to the tank and mixing the diluent withthe delumped waste to form a mixture; the method may further compriseunloading the mixture at the burning facility to enable incineration ofthe mixture.

The foregoing are just a few examples of the invention. Additionalaspects of inventive concepts and embodiments of the invention are setforth in part in the description which follows, and in part will beapparent from the description, or may be learned by practice of theinvention. The objects and advantages of the invention will be realizedand attained by the elements and combinations pointed out in theappended claims.

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate one embodiment and together withthe description, serve to explain various alternative principles of theinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is flow chart of a method for cleaning refinery tanks containingwaste, and disposal of the waste, according to embodiments of thepresent disclosure.

FIG. 2 is a top perspective view of a portion of a mixing apparatus,according to embodiments of the present disclosure.

FIG. 3 is a bottom perspective view of a portion of a mixing apparatus,according to embodiments of the present disclosure.

FIG. 4 is flow chart of a method for removing a substance from arefinery tank, according to embodiments of the present disclosure.

FIG. 5 depicts a method of evacuating a refinery tank containing waste,according to embodiments of the present disclosure.

FIG. 6 is pictoral view of a conveyor apparatus at a refinery tank siteconveying waste material from a refinery tank to a mobile tank,according to embodiments of the present disclosure.

FIG. 7 is a perspective view of a hopper of a conveyor apparatus,according to embodiments of the present disclosure.

FIG. 8 is a cross-sectional side view of a modified pneumatic trailer,according to embodiments of the present disclosure.

FIG. 9 is perspective view of a mixer, according to embodiments of thepresent disclosure.

FIG. 10 is a flow chart of a method of disposing of solid refinerywaste, according to embodiments of the present disclosure.

DESCRIPTION OF THE EMBODIMENTS

Reference will now be made in detail to exemplary embodiments of thepresent disclosure, examples of which are illustrated in theaccompanying drawings. Wherever possible, the same reference numberswill be used throughout the drawings to refer to the same or like parts.

Generally described, the present disclosure is directed to methods andequipment for cleaning ground tanks containing waste including solids ona tank bottom, and methods and equipment for waste disposal. As usedherein and throughout the disclosure, the term “ground tank” may referto any reservoir, mobile or stationary, that is typically maintained ina fixed location. The ground tank may be adapted to contain a substanceused in a process of converting raw material into products of value(e.g., oil, gasoline, etc.) and may be, for example, a refinery tank. Incertain embodiments, the substance may be hazardous and the ground tankmay be sealed to prevent leakage of the hazardous materials. In someembodiments, the ground tank may be a stationary tank having a circularshape with a diameter between 50 and 300 feet. In one exemplaryembodiment, the ground tank may be 120 feet in diameter and 40 feet inheight. However, no particular shape, size or other dimension limits theclaimed invention.

The ground tank may contain waste including solids on a tank bottom. Asused herein and throughout the disclosure, the term “waste” may refer toany excess of an industrial process. In the context of oil refining, itmay include byproducts of the refinement process. The waste may have adensity higher than 9.5 lb per gallon, and may include solidconstituents. Exemplary solid constituents that may be found on a tankbottom include dirt, sand, grit, paraffin, wax, emulsified, oil, etc. Asused herein, the term “solids” is used broadly to include allsedimentary material having a viscosity greater than non-sedimentarymaterial in the tank. The waste may accumulate inside the refinery tankover time, and may undermine the productivity of the tank. For example,a typical tank 120 feet in diameter and 40 feet tall may be completelyout of capacity when the waste reaches a height of 30 feet. Even beforethen, additional build-up may result in diminished efficiency.

FIG. 1 is an overview of an exemplary method of cleaning or emptyingground tanks containing waste, and disposing of the waste. In thefigures and the embodiments discussed below, the ground tank isillustrated and described as a refinery tank, it should be understood,however, that the invention is not limited to a particular type ofground tank or a particular usage. In a first step (step 110), waste maybe removed from a refinery tank using a mixing apparatus from a top ofthe refinery tank. The mixing apparatus may agitate an upper level ofthe waste into a pumpable form to enable the waste to be evacuated fromthe tank. A second step of the removal process (step 120), may includecutting an opening in a side of the refinery tank to enable entrance ofexcavation equipment such as, for example, a front end loader such as aBobcat®, to excavate solid waste. The solid waste may be loaded onto amobile tank and transported to a burning facility (step 130). As usedherein and throughout the disclosure, the term “burning facility” mayrefer to a facilitate that provides incineration services, such as acement kiln or a waste disposal site. Diluents may be added to the solidwaste and may be mixed with the solid waste in the mobile tank, tofacilitate removal of the solids from the tank, and to facilitateburning (step 140). It will be understood that certain embodiments maynot require all of the steps described above, and in other embodiments,additional steps may be added.

FIGS. 2 and 3 illustrate an exemplary mixing apparatus 200 for mixingtank contents including solid waste or other sedimentary materials. Asused herein the term “mixing apparatus” may refer to any device adaptedor configured to agitate the contents of a refinery tank 10. The mixingapparatus may enable extraction of sedimentary materials during a firstphase of the removal method, thereby freeing capacity within refinerytank 10. As used herein the term “sedimentary materials,” may refer tosolid constituents that settle to the bottom of a liquid. Using themethod and equipment discussed below, waste levels may go from 30 feetor more to 3 feet or less within refinery tank 10, without takingrefinery tank 10 out of service, although embodiments of the inventionmay include taking the refinery tank out of service during a wasteremoval process.

Mixing apparatus 200 may include an agitator 210 (FIG. 3). As usedherein and throughout the disclosure, the term “agitator” may refer toany apparatus configured to stir a substance that includes liquid andsolid constituents. Agitator 210 may be inserted through a first opening15 of refinery tank 10 to enable mixing of tank contents. First opening15 may be positioned on any surface of refinery tank 10. In theexemplary embodiment, first opening 15 may be formed on a top 12 ofrefinery tank 10. First opening 15 on top 12 of refinery tank 10 may be,for example, a manhole opening or any other opening in the tank wall. Asused herein and throughout the disclosure, the term “manhole opening”and “opening” may refer to any aperture large enough to permit insertionof a mixing apparatus. The manhole opening may be cut specifically foruse in removing waste from refinery tank 10 or may be part of refinerytank 10. Although only one opening on top 12 of refinery tank 10 isshown, it will be understood that additional openings on top 12 ofrefinery tank 10 may be provided.

In some embodiments, agitator 210 may be connected to a boom or support.As used herein and throughout the disclosure, the term “boom” may referto any means to extend a reach of an agitator. By way of example only,the boom may be associated with a wheeled chassis and/or may be adaptedto be connected to a vehicle. Agitator 210 may be supported by anelongated and expandable agitator support 220 (FIG. 2). As used hereinand throughout the disclosure, the term “expandable agitator support”may refer to a support whose length can be altered. For example,expandable agitator support 220 may include a structure configured tohold agitator 210 during a mixing process and enable changing the depthof agitator 210 within refinery tank 10.

As shown in FIG. 3, agitator 210 may be connected to expandable agitatorsupport 220 via a mount 226 located proximate a distal end 222 ofexpandable agitator support 220. Agitator 210 may include a first motor212, a rotatable shaft 214, and at least one blade 216 connected toshaft 214. First motor 212 may be any known type of non-sparking motorincluding, for example, a hydraulic motor configured to rotate shaft214. Agitator 210 may include any number of blades 216 in anyconstruction or arrangement configured to mix the tank contents whenshaft 214 is rotated. In some embodiments, agitator 210 may be amono-spin mixer with a 300-600 horse power motor. The mono-spin mixermay be about 20 feet long and 8 feet high and 8 feet wide, having atleast one blade between 15 to 25 inches. It will be understood thatother agitators, including agitators with numerous other constructionsand/or blade arrangements may be used.

Expandable agitator support 220 may be any known structure configured tohold or otherwise structurally support agitator 210 while agitator 210operates within refinery tank 10. To this end, agitator support 220 maybe an elongated and rigid support such as, for example, a solid rod orhollow tube. Expandable agitator support 220 may be made from materialsknown to one of ordinary skill in the art having sufficient durabilityto support agitator 210. Such materials may include, but are not limitedto stainless steel, aluminum, other metals, and composites. It iscontemplated that expandable agitator support 220 may be constructedfrom a single piece of material or may be made of multiple segments ofeither joined or un-joined material.

In an exemplary embodiment, expandable agitator support 220 may beformed of a plurality of detachable sections 234 (FIG. 2). Detachablesection 234 may enable a length of expandable agitator support 220 to beselectively altered. In particular, by adding and/or subtractingdetachable sections to or from support 220, the length of support 220may be changed. In the exemplary embodiment, expandable agitator support220 may be formed of at least seven detachable sections 234. It will beunderstood that a greater or lesser number of sections 234 may beprovided. Each detachable section may be between 10-50 inches, andpreferably about 25 inches.

Each detachable section 234 may include at least one flange 236. As usedherein and throughout the disclosure, the term “flange” may refer to anyconnector. For example, flange 236 may be a protrusion on eachdetachable section 234, enabling adjacent sections to be connected toeach other by bolting, fastening, or any other locking mechanism. Insome embodiments, a flange 236 may be located on both ends of eachdetachable section 234. In an exemplary embodiment, a flange 236 mayhave a circular or semi-circular shape and may be located on both endsof each detachable section 234.

In some embodiments, expandable agitator support 220 may form a portionof a vacuum tube. As used herein and throughout the disclosure, the term“vacuum tube” may refer to a conduit configured to convey a substance,either by a pump (or other force applicator) on an upstream side of theflow or a downstream side of the flow. The vacuum tube may beconstructed from a flexible hose, a rigid conduit, or from a combinationthereof.

In some embodiments, expandable agitator support 220 may include thevacuum tube having a channel for removing material from the tank. Forexample, expandable agitator support 220 may have a tubular structureincluding a distal end opening (not shown) and a channel extendingtherethrough, thus forming the vacuum tube. Mount 226 may be configuredto support the distal end opening of the vacuum tube proximate theagitator, such that when the agitator mixes material in refinery tank10, the opening of the vacuum tube is positioned to draw materialtherethrough. The channel may be configured for evacuating material fromrefinery tank 10 through agitator support 220. In other embodiments, thechannel may receive the vacuum tube. In those embodiments, the channelmay have an inner diameter of for example, 8 inches and the vacuum tubemay have an inner diameter of, for example, 6 inches. The vacuum tubemay extend through the channel and may be, for example, a rubber hose ora rubber tube.

In some embodiments, the vacuum tube may be coupled to at least onepump. The at least one pump may be, for example, a Viking gear pump. Inother embodiments, the vacuum tube may be coupled to a plurality ofpumps, e.g., two Viking gear pumps in series. In one example, theplurality of pumps may be connected to an outer pipe 232, extending froma proximal end 224 of expandable agitator support 220, and may providesuction for the removal of tank contents. In another embodiment, theplurality of pumps may be spread out along the vacuum tube. For example,a first pump may be configured for location inside refinery tank 10 andthe second pump may be configured for location external to refinery tank10. In this embodiment, a flexible tube may be used as a vacuum tube,and may define a flow path between the first pump ad the second pump.

In an exemplary embodiment, a pump 228 is positioned adjacent distal end222 of support 220 to draw material from refinery tank 10 into thevacuum tube (FIG. 3). Pump 228 may be, for example, a Viking gear pump.One of ordinary skill in the art will recognize, however, that pump 228may be any other known pump known configured to pump tank contents. Pump228 may be supported by mount 226, and driven by a second motor 230. Inparticular, mount 226 may be configured to support agitator 212 and pump228 adjacent each other proximate the distal end opening of the vacuumtube and in a manner such that when agitator 212 mixes contents inrefinery tank 10, the contents may be withdrawn through the distal endopening of the vacuum tube via pump 228. Second motor 230 may be anyknown type of non-sparking motor including, for example, a hydraulicmotor. The material in the vacuum tube may go through expandableagitator support 220 into outer pipe 232. An output end of the outerpipe 232 may be connected to a top of a tank trailer such as, forexample, a Roberoller™ agitator tanker trailer, offered by SumterTransport of Sumter, S.C.

In some embodiments, a frame 240 may be provided. Frame 240 may beconfigured for disposition adjacent first opening 15 in top 12 ofrefinery tank 10. As used herein and throughout the disclosure, the term“frame” refers to any structure for aiding in connection of a mixerstructure to a tank opening. For example, frame 240 may be a unitaryframe that partially or fully surrounds first opening 15. It iscontemplated that frame 240 may be connected to refinery tank 10 by anyknown connector including, but not limited to, bolts, fastener, or anyother locking mechanism.

In some embodiments, at least one actuatable connector 250 may beprovided for interconnecting frame 240 to expandable agitator support220 (FIG. 2). As used herein and throughout the disclosure, the term“actutable connector” may refer to any connector that may be used toadjust the length and/or position of an agitator support. In theexemplary embodiment, actuatable connector 250 may enable lifting of afirst portion 252 of agitator support 220 above frame 240 while a secondportion 254 of agitator support 220 below frame 240 is maintained in asubstantially fixed position with respect to frame 240. In this manner,actuatable connector 250 may facilitate the formation of a gap betweenfirst portion 252 of agitator support 220 and a second portion 254 ofagitator support 220. At least one detachable section 234 may beinserted into the gap. A first flange 236 (e.g., upper flange) on theinserted detachable section 236 may be connected to first portion 252and a second flange 236 (e.g., lower flange) on the inserted detachablesection may be connected to the second portion 254 when inserted in thegap. In this manner, the at least one actuatable connector 250 mayenable the otherwise substantially rigid agitator support 220 to beelongated. In some embodiments, at least one actuatable connector 250may be used to iteratively lower the agitator support 220 into refinerytank 10 as refinery tank 10 is emptied.

Actuatable connector 250 may include at least one lifting mechanism forselectively lifting first portion 252 in order to cause the gap. As usedherein and throughout the disclosure, the term “lifting mechanism” mayrefer to any device capable of lifting and/or lowering an agitatorsupport. In some embodiments, the lifting mechanism may include, forexample, an actuator, such as one or more hydraulic cylinders.

In some embodiments, the lifting mechanism may operate in a first modefor lifting and lowering agitator support 220 when agitator support 220is detached from frame 240, and may further operate in a second modewhen agitator support 220 is affixed to frame 240 to enable selectiveinsertion and removal of one or more detachable sections 234 fromagitator support 220. In other embodiments, the lifting mechanism mayselectively lift the first portion 252 of agitator support 220 in orderto form a gap in the support structure, and lower first portion 252 whenthe at least one detachable section 234 is inserted and coupled tosecond portion 254.

In some embodiments, the lifting mechanism may include a chain, at leastone hoist, a belt, a gear, a hydraulic cylinder, an air cylinder, ascrew, or at least one pneumatic cylinder. In FIG. 2, two liftingmechanisms are provided. In the depicted embodiments, the two liftingmechanism are actuators e.g., pneumatic cylinders 256.

Actuatable connector 250 may also enable agitator support 220 to beattached or detached from frame 240. For example, actuatable connector250 may include one or more connectors 251 such as, for example, hooks,fasteners, and/or bolts. Connectors 251 may be configured to secureagitator support 220 to frame 240 during the mixing process and detachagitator support 220 from frame 240 when it is desired to lower agitator210.

Referring to FIG. 4, a method for removing a substance from a refinerytank will now be discussed. A first step of the method may includeinserting an agitator 210 into a first topening 15 on a top 12 of arefinery tank 10 (step 410). In some embodiments, the mixing apparatus200 may include an agitator 210 connected to an elongated and expandableagitator support 220. Other mixing apparatuses, however, arecontemplated.

In order to insert agitator 210 into tank 10, mixing apparatus 200 maybe positioned above a top 12 of refinery tank 10 using a crane via ahook 258 (FIG. 2). Hook 258 may enable agitator 210 to be lowered by thecrane, in order to position agitator 210 in first opening 15 on top 12of refinery tank 10. Once agitator 210 is inserted into first opening 15on top 12 of refinery tank 10, the next step may include securingexpandable agitator support 220 to connector 251 located at a peripheryof first opening 15 on top 12 of refinery tank 10 to secure agitator 210at a first depth within refinery tank 10 (step 420 in FIG. 4). The firstdepth, i.e., the initial depth of agitator 210 may be determined basedon measurements of the tank contents and a thickness level of the tankcontents. For example, sampling devices may be used to determine theextent of solids in refinery tank 10, and the BTU level. Othermeasurements are contemplated.

Mixing of tank contents which may include a substance having liquid andsolid constituents may then begin (step 430). Prior to mixing, however,excess liquid may be removed. In some embodiments, a portion of theliquid may be left within refinery tank 10 to be used as diluents in themixing process. As used herein and throughout the disclosure, the term“diluent” may refer to any liquid added to the substance being mixedthat is used to decrease the viscosity of the mixture. Examples ofdiluents may include, but are not limited to, water, naphtha,condensate, kerosene, and/or any other diluent known to one of ordinaryskill in the art.

Upon mixing the substance, agitator 210 may create blended areas and/orpools within refinery tank 10. Each blended area may be, for example,about 15-35 feet in width and 5-15 feet in depth. It is contemplatedthat, in some embodiments, a plurality of agitators 210 may be used toform multiple blended areas within refinery tank 10. The blended areasmay facilitate pumping of the materials from refinery tank 10.

In some embodiments, mixing apparatus 200 may include at least one pumpfor pumping the mixed substance from refinery tank 10 through agitatorsupport 220 (step 440). In particular, the substance may be drawnthrough a vacuum tube, which may include expandable agitator support 220and an outer pipe 232. In other embodiments, a plurality of pumps may beprovided to create a flow path for drawing the substance from refinerytank 10. In particular, a first pump may be included to push thesubstance into an opening in expandable agitator support 220 and asecond pump may be provided suction through the vacuum tube.

It is contemplated that, in some embodiments, the substance may besimultaneously mixed and pumped from refinery tank 10. In particular,mixing apparatus 200 may include a control configured to cause firstmotor 212 associated with agitator 210 and second motor 230 associatedwith first pump 228 to operate simultaneously. In other embodiments,first motor 212 and second motor 230 may operate independently of eachother.

It is possible, while pumping the mixed substance from the tank, for thelevel of substance within the tank to drop below first pump 218. Whenthis occurs, the mixing and pumping steps may be suspended (step 450),and agitator support 220 may be un-secured from frame 240 via connectors251 (step 460). Actuatable connector 250 may then be used to lift afirst portion 252 of agitator support 220 above frame 240 while a secondportion 254 of agitator support 220 below frame 240 is maintained in asubstantially fixed position with respect to frame 240 to form a gaptherebetween. At least one detachable section 234 may then be insertedinto the gap to elongate agitator support 220 and lower agitator 210 toa second depth within refinery tank 10 deeper than the first depth (step470). Lowering agitator 210 may, in some embodiments, compriseenergizing an actuator 256 or any other comparable method. Afterlowering the agitator to a second depth, agitator support 220 may bere-secured to frame 240 (step 480) to resume pumping and mixing at thesecond depth (step 490). It is contemplated that the method may includeiteratively mixing, pumping, un-securing, lowering, re-securing, andresuming mixing a plurality of times and over a depth of at least 5feet, at least 10 feet, at least 20 feet, at least 30 feet, or untilrefinery tank 10 is empty.

In some embodiments, the pumped substance may be conveyed to a mobiletank. For example, the pumped substance may be drawn through the vacuumtube directly into a mobile tank. The mobile tank may transport thesubstance to a burning facility. The mobile tank may, in certainembodiments, have an agitator built in and adapted to run during most ofthe transportation and prevent the solids from settling. In one example,the pumped substance may be loaded into a Roberoller™ agitator tankertrailer to be transported to a burning facility.

When a substance is no longer free to flow into any of the blendedareas/pools or, in the alternative, when the rate of substance enteringthe blended areas/pools is lower than a predetermined threshold (e.g.,140 tons per day) such that the substance cannot be pumped from refinerytank 10 using the method described above, a second removal process maybegin. During the second removal process, refinery tank 10 may be takenout of service (if it had been in service up to this point), and thesolid waste may be excavated from refinery tank 10. The second removalprocess may also be used when a refinery tank is partially filled foreasier access to the waste material. An exemplary method is illustratedin FIG. 5.

Referring to FIG. 5, a first step of the method may involve cutting anopening 20 on a side of refinery tank 10 (step 510). The opening 20 maybe the first opening formed on refinery tank 10, or may be the secondopening formed on refinery tank 10, e.g., the opening may be formed on aside wall of refinery tank 10 after first opening on top 12 of refinerytank 10 has been formed. Opening 20 may be formed using known methods.In an exemplary embodiment, opening 20 may be formed using a pressurewater jet cutting apparatus. This is only one example as any devicecapable of safely cutting opening 20 may be used.

Opening 20 may be formed on any portion of refinery tank 10. In certainembodiments, the opening 20 may be formed in a side wall of refinerytank 10 and at a height such that a bottom edge of the opening may bespaced from the tank bottom. In some embodiments, opening 20 may bespaced between 5 to 20 feet from the tank bottom. The opening may haveany size, shape, and/or dimensions to enable insertion of a mixingapparatus (e.g., an agitator). For example, the dimensions of opening 20may have a height between, for example, 2 and 10 feet and a widthbetween, for example, 3 and 15 feet. In an exemplary embodiment, opening20 may be 10×10 feet located about 8 feet from the tank bottom.

In some embodiments, the distance between a level of waste insiderefinery tank 10 and a reference point may be measured to determine thedimensions of opening 20. In other embodiments, the waste may be sampledto determine the viscosity of the waste based on characteristics of thesample. If, for example, the sample contains a high liquid content, theliquids may be removed from tank 10. Additionally and/or alternativelymixing apparatus 200, discussed above, may be used to remove tankcontents prior to forming opening 20.

After second tank opening 20 is created, an agitator 532 may be insertedthrough opening 20 (step 520). In some embodiments, agitator 210 may bea mono-spin mixer with a 300-600 horse power motor. The mono-spin mixermay be about 20 feet long and 8 feet high and 8 feet wide, having atleast one blade between 15 to 25 inches. It will be understood thatother agitators, including agitators with numerous other constructionsand/or blade arrangements may be used.

In some embodiments, agitator 532 may be inserted into opening 20 usinga boom 534. Boom 534 may be associated with, for example, a forklift toextend agitator 532 into and out of opening 20 and up and down withinrefinery tank 10. In certain additional embodiments, boom 534 may beconfigured to rotate agitator 532 about 360 degrees. Accordingly,agitator 532 may be inserted into refinery tank 10 and positionedadjacent the solid waste.

Agitator 532 may be configured to agitate the solid waste in a firstarea to cause the waste in the first area to have a first viscositylower than a viscosity of waste in a second area at a periphery of orsurrounding the first area. In some embodiments, diluents may be addedto tank 10 during the mixing process. Examples of diluents may include,but is not limited to, water, naphtha, condensate, kerosene, and/or anyother diluent known to one of ordinary skill in the art. By mixing thesolid constituents in the first area with diluents, the viscosity of thefirst area may be lowered so that the solids may be removed via one ormore pumps (not shown). This may result in the first area containingmaterial that is more flowable than waste at a periphery of orsurrounding the first area. As used herein, the word “periphery”includes any portion of any border, and the term “surrounding,” includescomplete or partial bounding of a first area.

It is contemplated that, in certain embodiments, agitator 532 may be apivotal agitator having a pair of opposing thrust generators. In thoseembodiments, the pitch and angular orientation of agitator 532 may bealtered during the mixing process. For example, agitator 532 may beinserted through opening 20 in a first position such that one of thethrust generators substantially faces a tank bottom. This position maybe used to agitate and clear an area from the tank bottom. Additionallyand/or alternatively, thrust generators may be moved to a secondposition generally parallel to the tank bottom. In this position,agitator 532 may be capable of mixing a larger area of waste.

The agitated waste may be removed from the first area while maintainingthe waste of the second viscosity in the second area, thereby forming asafe room 536 in the refinery tank (step 530). For example, a flowablenature of waste of the first viscosity may be sufficient to enable thatwaste to be removed from the tank while a substantially non-flowablenature of the second viscosity may provide sufficient rigidity to theremaining waste to form a substantially non-flowable slope or wall,thereby creating a safe room within refinery tank 10. As used herein andthroughout the disclosure, the term “safe room” refers to an area (e.g.,a cavity) inside the tank without waste substance. The safe room 536 maydefine walls and a floor substantially coincident with the tank bottom.In some embodiments, the safe room 536 may be formed by removing aportion of the solid waste to form a cavity, where the waste substanceitself forms some of the walls of the safe room. In alternativeembodiments, one or more structures may be used to create safe room 536or support at least one wall of safe room 536.

The dimensions of safe room 536 may depend on the type of substance inrefinery tank 10. In some embodiments, safe room 530 may extend from anarea adjacent the bottom edge of second tank opening 20 towards the tankbottom. According to one example, the safe room may be about 30 feethigh and can have a circumference of about 90 feet.

It is contemplated that a method may include iteratively agitating andremoving waste until the first area is expanded to a depth proximate thetank bottom. To do so, the method may include: pumping in diluents andmixing the waste in the first area; pumping waste out; moving the boomslightly to the right and pumping waste out again; moving the boomslightly to the left and pumping waste out again; pumping in diluentsand further mixing; continuing to move the boom horizontally until theboom agitates the material to the right as far as possible, and to leftas far as possible; and then continuing to repeat the above process moredeeply into the refinery tank. This example procedure (pumping diluentsin, mixing, and pumping waste out) may be repeated until the floor ofthe refinery tank is reached. After reaching the tank bottom, the boommay be used inside of refinery tank 10 to enlarge the cavity. Inparticular, the boom may be used to create safe room 536 that extends totank bottom of refinery tank 10.

When working down all the way to the floor, a relatively steep slope 538of the solid waste may be formed. The slope 538 may be between 30degrees and 75 degrees from tank bottom to a back wall of refinery tank10. In some embodiments, the slope 538 may be between 30 and 60 degrees.Once slope 538 of the solid waste is formed, it is possible to go insiderefinery tank 10 and take samples of the solid waste in lower layers.The waste may be sampled to determine a minimum angle of repose of atleast one wall of safe room 536 based on characteristics of the sample.This may be used to confirm that the materials inside tank 10 are notgoing to start moving and potentially collapse when the next steps takeplace,

Over the next step, opening 20 may be expanded toward the tank bottom toenable entry of a movable excavator 542 into safe room 536 of refinerytank 10 (step 540). In some embodiments, opening 20 may be iterativelyexpanded downward a location above the floor of the first area as thefirst area is being expanded. Opening 20 may be expanded until opening20 has been expanded to a location above a floor of safe room 536. Asused herein and throughout the disclosure, the term “excavator” mayrefer to any machinery adapted to move a substance from one location toanother. Excavator 542 may be any excavator known to one of ordinaryskill in the art. In some embodiments, excavator 542 may be aself-propelling excavator. Two non-limiting examples of excavator 542include a Bobcat® skid-steer loader and a Caterpillar®mini wheel loader.Usually, there will be enough space for a Bobcat® to operate within therefinery tank since a typical refinery tank is 120-feet in diameter. Thepresent method, however, can also be implemented with different-sizedrefinery tanks—for example, a 60-foot tank and a 240-foot tank.

The distance between the tank bottom to a bottom of the first area maybe used as a reference to determine the dimensions of the expandedopening 30. In one example, the expanded opening 30 may have a maximumheight of over six feet. In other embodiments, a second opening may beformed on the side of refinery tank 10 separate from the first openingthat is formed on the side of refinery tank 10. In those embodiments,the combined height of the two openings may be over six feet. Theexpanded opening or second opening formed on the side of refinery tank10 may be cut using, for example, a pressure water jet cuttingapparatus. It will be understood that the expanded opening or secondopening may be cut using any other known method.

In some embodiments, a bottom edge of the opening 30 may be spaced anumber of feet from the tank bottom. For example, a bottom of theexpanded second tank opening 30 may be distanced from the tank bottom byless than three feet. In such instances, a ramp may be built to enableexcavator 542 to enter into refinery tank 10. The ramp (not shown) maybe placed near the expanded opening 30 for excavator 542 to be propelledinto safe room 536.

The excavator may be configured to remove waste of the second viscosityfrom the second area of refinery tank 10. While doing so, excavator 542may maintain a predetermined slope of at least one wall of safe room536. In particular, excavator 542 may maintain the predetermined slopeof, for example, less than 90 degrees. By way of another example, theslope may be between 30 degrees and 75 degrees extending from the bottomof the floor to the back of refinery tank 10. By creating a safe areawithin the tank, excavator 542 may move from outside tank 10 to thefloor of safe room 536. Within refinery tank 10, it is contemplated thatexcavator 542 may remove waste from one or more mounds and/or hillsincluding the sloped walls of safe room 536. In those instances,excavator 542 may scape the hill down while keeping the angle of thehill. Excavator 542 may scape each of the walls of the safe room,forming piles of solid waste material.

In some embodiments, the solid waste material removed from refinery tank10 may be transported to a burning facility to be disposed. To transportthe material, the solid waste may be loaded into a tank. The tank may bemounted on a mobile vehicle such as, for example, a trailer, truck, railcar, ship, barge, or boat or otherwise configured to be transported. Themobile tank may include an agitator therein.

In an exemplary embodiment shown in FIG. 6, the solid waste material maybe loaded from refinery tank 10 into a mobile tank 630 using a conveyingapparatus 600. Conveying apparatus 600 may be located adjacent thesecond expanded opening 30, with a portion of the apparatus extendingabove a manhole opening 632 on mobile tank 630. Material may be conveyedfrom second expanded opening 30 to manhole opening 632 to be loaded intomobile tank 630. It is contemplated that, in some embodiments, one ormore connectors may be provided to secure conveying apparatus 600 totank 630.

Conveying apparatus 600 may be an assembly of components including aconveyor 610 and at least one hopper 620, 621, at least one of whichcontains a delumper. The term “conveyor” as used herein and throughoutthe disclosure may refer to any know structure configured to convey asubstance from a first location to a second location. For example,conveyor 610 may be a belt conveyor, a vibrating conveyor, a flexibleconveyor, or any other known conveyor. In some embodiments, conveyor 610may be associated with a mobile vehicle (e.g., a trailer or truck) or astationary system. In an exemplary embodiment, conveyor 610 may be amobile belt conveyor. In additional and/or alternative embodiments,conveyor 610 may include one or more actuators to adjust the height ofat least a portion of conveyor 610 to facilitate the conveyance of thewaste material.

As used herein and throughout the disclosure, the term “delumping” and“delumper” refers to processes and structures that makes larger piecessmaller (lump reduction) As used herein, such processes and structuresmay involve one or more of shredding, chopping, cutting, mashing,fragmenting, squeezing, turning, rolling, or any other structure/processthat accomplishes size reduction. Thus, delumping, as used herein, doesnot necessarily imply an absence of lumps, but rather that at least somelarge lumps are made smaller using a lump reducer.

The at least one hopper 620, 621 may be located on either end ofconveyor 610, and may be configured to receive and break apart solidwaste. An exemplary hopper 621 is shown in FIG. 7. As shown in FIG. 7,hopper 621 may include a bin 622 and a plurality of blades 624positioned within bin 622. It will be understood that blades 624 mayhave any construction or arrangement. The plurality of blades 624 may beused for delumping the solid waste. For example, as blades 624 turn,they I may be configured to chop and/or shred the solid waste locatedwithin bin 622 so that the solid waste may be small enough to passthrough openings 626 formed in a bottom of bin 622. In some embodiments,the plurality of blades 624 may be configured to fragment the solidwaste to form a plurality of clumps weighing less than, for example, 20lbs.

Referring back to FIG. 6, in some embodiments, hopper 621 may be locatedat an end of conveyor 610 positioned adjacent expanded opening 30. Inthis embodiment, the excavated solid waste may be inserted into hopper621, delumped, and placed on conveyor 610 via openings 626 to beconveyed to mobile tank 630. In additional and/or alternativeembodiments, the at least one hopper 620 may be located above manholeopening 632. In this embodiment, waste material may be conveyed to bin622 of hopper 620, delumped, and then dropped through openings 626 intomobile tank 630. In some embodiments, the fragmented waste material maybe dropped into a funnel for conveying the material to an individualcompartment of mobile tank 630. Blades 624 may be contained in one orboth hoppers. Alternatively, delumping may occur at an intermediatelocation prior to loading onto the conveyor system.

Mobile tank 630 may be configured to transport the delumped waste to aburning facility. In some embodiments, the delumped waste may betransported in a solid form. At the burning facility, diluents may bepumped into mobile tank 630 and blended with the delumped waste to forma pumpable mixture. The mixture may then be pumped out of one or moreoutlet openings on mobile tank 630. In other embodiments, the diluentmay be added near the ground tank site.

In order to introduce diluents into mobile tank 630, a head space may beleft between a top level of the delumped waste in mobile tank 630 and atop wall of mobile tank 630. In some embodiments, mobile tank 630 may besized to contain at least 20,000 pounds of the solids refinery waste,while maintaining a head space for at least 3,000 pounds of diluent. Inthose embodiments, the head space may be larger than 12 inches. In otherembodiments, mobile tank 630 may be configured to contain at least50,000 pounds of the solid refinery waste.

In some embodiments, mobile tank 630 may be a pneumatic trailer. As usedherein and throughout the disclosure, the term “pneumatic trailer” mayrefer to any vehicle having a tank with sections that are eitherpartially or completely separated from each other. For example, mobiletank 630 may be similar to those used for example, to transport grainslike wheat and oats, powders like cement, and liquids like milk oralcohol. These pneumatic tankers may have three un-separatedcompartments, which may enable materials to go from one compartment toanother compartment.

In the present disclosure, mobile tank 630 may be a modified pneumatictrailer as shown in FIG. 8. In particular, mobile tank 630 may have atleast two compartments 636 separated by a buffer 638. Buffer 638 may be,for example, a vertical wall extending from a bottom wall of the tank tosubstantially a top wall 635 of the tank to limit the migration of solidwaste between compartments when, for example, at least one diluent isadded to one of the plurality of compartments. In the exemplaryembodiment shown in FIG. 8, mobile tank 630 may include threecompartments 636 separated by two buffers 638. It will be understoodthat a greater or lesser number of buffers and compartments may beprovided.

Each compartment 636 may be in fluid communication with a manholeopening 632, a fluid valve 640, and an outlet opening 642. Each manholeopening 632 may be associated with one of the plurality of compartments636 and sized to enable an agitator or other type of mixer associatedwith a mixing apparatus 700 (FIG. 9) to pass therethrough. Eachcompartment 636 may have at least one sloped floor wall 634 (FIG. 8) forenabling the mixed solid refinery waste to migrate by gravity towardoutlet opening 642 in a bottom of each compartment 636. A fluid valve640 may be associated with each outlet opening 642. Each fluid valve 640may be sized to permit an emulsion of the solid refinery waste and atleast one diluent to pass therethrough in flowable form. Fluid valves640 may be ball valves or double valves designed for liquids. Inparticular, fluid valves 640 may be configured to off-load tank contentswith the assistance of at least one pump. In one example, fluid valves640 may be ball valves having a diameter of four inches.

Mixing apparatus 700 (FIG. 9) may be configured for mixing refinerysolid waste in a mobile tank having at least one compartment with slopedfloor walls, such as, for example, mobile tank 630. Mixing apparatus 700may be any known type of mixer including, for example, an agitatorhaving an elongated shaft and at least one blade connected to the shaftconfigured to mix the tank contents when the shaft is rotated.

Mixing apparatus 700 may include at least one actuator operable forlifting and lowering at least a portion of the agitator in mobile tank630 to enable blending of solids and liquid constituents in mobile tank630. The upward and downward motion of mixing apparatus 700 may enablemixing apparatus 700 to remove refinery solid waste from pockets on theside of the conically shaped compartments 636 of mobile tank 630. Theone or more actuators may be, for example, air-actuated cylinders orhydraulic-actuated cylinders to actuate the mixing apparatus up and downto mix the refinery solid waste.

In some embodiments, at least one external support may be configured fordisposition adjacent a manhole opening 632 in a top of mobile tank 630.The support may be any know support for supporting the agitator ofmixing apparatus 700 when mixing the refinery solid waste in mobile tank630. In one example, manhole openings 632 may be modified to receive oneor more connectors 650 to fasten, bolt, or otherwise lock mixingapparatus 700 to mobile tank 630 during the mixing process. In thismanner, hazardous gas may be prevented from escaping mobile tank 630. Insome additional embodiments, connectors 650 may be constructed forconnection to mixing apparatus 700 in a manner permitting mixingapparatus 700 to be controllably lowered into mobile tank 630 whilemixing tank contents. In the exemplary embodiment of FIG. 9, oneconnector is shown. It will be understood, however, that a greaternumber of connectors may be provided.

In some additional embodiments, mobile tank 630 may include an opening720. Opening 720 may be configured form a fluid seal with a fluidpressure system (not shown). The fluid pressure system may be configuredto maintain a pressure inside tank lower than a pressure outside tank.Additionally, the fluid pressure system may be configured to evacuategas from the tank when a diluent is added to the tank. In additionaland/or alternative embodiments, opening 720 may also be used to sampletank contents to determine when a homogenous mixture has been formedthat may be pumped to the burning facility.

Referring to FIG. 10, a method for disposing of solid refinery wastewill now be discussed. As shown in FIG. 10, a first step of the methodincludes removing solid waste constituents from inside refinery tank 10using excavation machinery such as, for example, an excavator (step810). This step may be performed in accordance with the methodsdescribed above or any other method known to one of ordinary skill inthe art.

In some embodiments, the excavated solid waste may be delumped andconveyed into a mobile tank 630 (step 820). The delumping and theconveying may be performed by a single apparatus or separateapparatuses. In one embodiment, a conveying apparatus 600 may beprovided with a bin 621 for receiving the excavated solid waste andfeeding the solid waste to a delumping device (e.g., blades 624). Thedelumping device may deposit the delumped solids on a conveyor 610,which may be arranged to deposit the delumped waste into a manholeopening 632 on mobile tank 630. In another embodiment, the excavatedmaterials may be placed onto conveyor 610, which may then convey thematerials to bin 622 located above or within manhole opening 632. Othermethods of delumping and/or conveying the waste material iscontemplated.

The delumped waste may be loaded into a compartment 636 within mobiletank 630. Mobile tank 630 may include a single compartment or two ormore compartments 636. In those embodiments, a funnel may be provided toconvey the delumped material to an individual compartment 636. Eachcompartment 636 may be partially filled or completely filled. Forexample, in some embodiments a head space may be left between a toplevel of the delumped solid waste and a top wall 635 of mobile tank 630(step 830). The head space may be, for example, larger than 12 inches.

At least one diluent may be added to the head space (step 850). Examplesof diluents may include, but is not limited to, water, naphtha,condensate, kerosene, and/or any other diluent known to one of ordinaryskill in the art. In some embodiments, the diluent may be added aftertransporting the delumped solid waste to a burning facility (step 840).In those embodiments, the diluent may be mixed with the delumped wasteat the burning facility using a mixing apparatus. In other embodiments,the diluent may be added before transporting the delumped solid waste toa burning facility, and at least partially mixed during transportation.

The mixing apparatus may be any known apparatus including a mixerincluding, for example, an agitator for mixing the solid refinery waste.In some embodiments, the mixing apparatus may be configured forinsertion into at least one manhole opening 632 to mix tank contents. Inother contemplated embodiments, each compartment 636 of mobile tank mayinclude a mixing apparatus built in for mixing tank contents duringtransportation.

In an exemplary embodiment, a mixing apparatus 700 may be inserted intomanhole opening 632 and bolted to manhole opening 632 via one or moreconnectors 650. During the mixing process, mixing apparatus 700 may beconfigured to agitate the tank contents, including the solid refinerywaste. In some embodiments, agitating may include moving at least aportion of the mixing apparatus 700 vertically within mobile tank 630.In some additional and/or alternative embodiments, agitating may includeagitating a central portion of an individual compartment 636 to causethe mixture to flow down sloped floor walls towards fluid valve 640. Thehomogenous mixture may then be pumped from mobile tank 630 throughoutlet opening 642 (step 860).

In some embodiments, the mixing and pumping may occur in an individualcompartment 636 before unloading an adjacent compartment 636. In theseembodiments, a single mixing apparatus 700 may be used to agitate afirst compartment 636 to form a homogenous mixture. After the homogenousmixture has been emptied from the compartment, the mixer 700 may beinserted into a manhole opening associated with a second compartment formixing. In other embodiments, multiple mixing apparatuses 700 may beprovided so that the mixing and pumping from the compartment 636 mayoccur simultaneously.

In some embodiments, the mixing and the pumping may occur sequentially.In those embodiments, the mixture may be sampled via opening 720 duringthe mixing process to determine a mixing resistance of mixer 700. Themixture may be off-loaded from tank 630 only after a predeterminedmixing resistance is achieved. The predetermined mixing resistance maycorrespond to a resistance when the mixture is substantially homogenousand flowable. Additionally and/or alternatively, a pressure controlsystem may be coupled to mobile tank 630 during the mixing and pumpingprocess. The pressure control system may be configured to maintain apressure inside the mobile tank lower than a pressure outside the mobiletank. The pressure system may be further configured to evacuate gas frommobile tank 630 when the diluent is added to achieve a desired fluidpressure. In some embodiments, the mixture may be off-loaded from tank630 only after a stable fluid pressure has been achieved. The stablefluid pressure may indicate, for example, that the solids and diluentsare mixed and the mixture is ready to be pumped. In other embodiments,the mixing and the pumping may occur simultaneously.

Other embodiments of the invention will be apparent to those skilled inthe art from consideration of the specification and practice of theinvention disclosed herein. It is intended that the specification andexamples be considered as exemplary only, with a true scope and spiritof the invention being indicated by the following claims.

What is claimed is:
 1. A method of evacuating a refinery tank containing waste with solid constituents, the method comprising: inserting an agitator on a boom through a first opening on a side of the refinery tank, the first opening having been cut in the refinery tank above a top surface of waste in the refinery tank, and wherein a bottom edge of the opening is spaced a number of feet from a bottom of the refinery tank; agitating waste in a first area of the refinery tank to cause the waste in the first area to have a first viscosity lower than a second viscosity of waste in a second area at a periphery of the first area; removing agitated waste from the first area while maintaining the waste of the second viscosity in the second area, thereby forming a safe room in the refinery tank, wherein a floor of the safe room is substantially coincident with the bottom of the refinery tank; expanding the first opening toward the floor of the safe room to enable entry of a movable excavator into the safe room of the refinery tank; and removing waste of the second viscosity from the second area of the refinery tank using the movable excavator.
 2. The method of claim 1, further comprising adding diluent to the refinery tank and wherein agitating the waste in the first area includes mixing the diluent with the solid constituents in the first area.
 3. The method of claim 1, wherein at least one wall of the safe room is formed with a slope of between 30 degrees and 75 degrees.
 4. The method of claim 1, further comprising adding a support to at least one wall of the safe room.
 5. The method of claim 1, further comprising sampling the waste in the refinery tank and determining a minimum angle of repose of at least one wall of the waste solids in the safe room based on characteristics of the sample.
 6. The method of claim 1, further comprising installing a ramp proximate a threshold of the opening to enable the excavator to be propelled into the safe room.
 7. The method of claim 1, wherein the expanded opening has as maximum height of over six feet.
 8. The method of claim 1, wherein a bottom of the expanded opening is distanced from the bottom of the refinery tank by less than three feet.
 9. The method of claim 1, wherein during removing excavator removes waste in a manner maintaining a predetermined slope of greater than 90 degrees on at least one wall of the safe room.
 10. The method of claim 1, further comprising measuring a distance between a level of waste inside the refinery tank and a reference point.
 11. The method of claim 1, wherein the movable excavator is self-propelled.
 12. A method of evacuating a refinery tank containing waste with solid constituents, the method comprising: inserting an agitator through a first opening in a top of the refinery tank; agitating waste in a first area of the refinery tank to cause the waste in the first area to have a first viscosity greater than a second viscosity of waste in a second area adjacent the first area; removing agitated waste of the first viscosity through the top of the refinery tank; opening a second opening on the side of the refinery tank, wherein a bottom edge of the second opening is at least one foot above a top surface of the waste in the refinery tank; removing waste of the second viscosity from the second area of the refinery tank via the second opening; expanding the second opening downward toward a floor of the refinery tank; inserting an excavator into the refinery tank via the expanded second opening; and removing waste of the second viscosity using the excavator.
 13. The method of claim 12, wherein a bottom edge of the expanded second opening is spaced a number of feet from a bottom of the refinery tank.
 14. The method of claim 12, wherein the bottom edge of the second opening is distanced from the bottom of the refinery tank by less than three feet.
 15. The method of claim 12, wherein a combined height of the first opening and the second opening is over six feet.
 16. The method of claim 12, wherein at least one of the first opening and the second opening is cut using a pressure water jet cutting apparatus.
 17. A method of evacuating a refinery tank containing waste with solid constituents, the method comprising: cutting a first opening in the refinery tank above an initial top level of waste; inserting an agitator into the refinery tank through a first opening; agitating the waste in a first area of the refinery tank to cause waste in the first area to have a viscosity greater than a viscosity of waste in a second area at a periphery of the first area; removing the waste from the first area; expanding the opening downward to a location above the bottom of the first area; agitating the waste at the bottom of the first area to cause waste beneath the bottom of the first area to have a viscosity greater than a viscosity of waste in a second area at a periphery of the first area; removing the waste from the bottom of the first area to reach an expanded bottom of the first area; and expanding the opening downward to a location above the expanded bottom of the first area.
 18. The method of claim 17, further comprising iteratively agitating, removing and expanding until the first area is expanded to a depth proximate a bottom of the refinery tank.
 19. The method of claim 17, further comprising sloping walls of the first area during removing in order to create a safe room in the first area.
 20. The method of claim 17, further including inserting a movable excavator into the safe room and evacuating the waste of the second viscosity from the second area using the excavator.
 21. The method of claim 20, wherein the movable excavator is self-propelled.
 22. The method of claim 17, further comprising measuring a distance from a bottom of the opening to a bottom of the first area, and using the measured distance as a reference for expanding the opening.
 23. The method of claim 17, wherein the first opening is cut in a side of the refinery tank, and wherein prior to cutting the first opening, a portion of the tank is agitated via an initial opening in a top of the refinery tank.
 24. The method of claim 17, further comprising moving waste from the tank to a lump reducer.
 25. The method of claim 24, further comprising delumping waste in the lump reducer using at least one blade.
 26. The method of claim 25, further comprising conveying the delumped waste to a manhole opening of a mobile tank.
 27. The method of claim 26, wherein conveying the delumped waste includes moving the delumped waste via a conveyor.
 28. The method of claim 26, further comprising moving the mobile tank to a burning facility.
 29. The method of claim 28, further comprising adding diluent to the tank and mixing the diluent with the delumped waste to form a mixture.
 30. The method of claim 29, further comprising unloading the mixture at the burning facility to enable incineration of the mixture. 